<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>center-5</title>
    <style>
        .big-box{
             width: 500px;
             height: 400px;
             background: green;
             text-align: center;
             }
           .box{
                line-height: 400px;
                border:1px solid blue;
            }
            img{
                vertical-align: middle;
                width:100px;
                height:auto;
            }
    </style>
</head>
<body>
<div class="big-box">
   <span class="box">
     <img src="img/use.png"/>
   </span>
</div>
</body>
</html>
